School of Material and Environmental Engineering, Shenzhen Polytechnic, Shenzhen 518055, China.
School of Civil and Environmental Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China.
Environ Int. 2022 Sep;167:107383. doi: 10.1016/j.envint.2022.107383. Epub 2022 Jun 29.
Iopamidol (IPM) is widely used in medical clinical examination and treatment and has immeasurable harm to the ecological environment. The combination of UV and sulfite (UV/sulfite) process was developed to degrade IPM in this study. In contrast to that almost no removal of IPM was observed under sulfite reduction alone, the UV/sulfite process could efficiently reductively degrade IPM with the observed rate constant (k) of 2.08 min, which was nearly 4 times that of UV irradiation alone. The major active species in the UV/sulfite process were identified as hydrated electrons (e) by employing active species scavengers. The influence of the initial pH, sulfite dosage, IPM concentration, UV intensity and common water matrix were evaluated. The degradation of IPM reached nearly 100% within only 2.5 min at pH 9, and k increased at higher initial sulfite dosages and greater UV intensities. HCO had a limited effect on the degradation of IPM, while humic acid (HA) was found to be a strong inhibitor in the UV/sulfite process. With the synergistic action of UV/sulfite, most of the iodine in IPM was found to release in the form of iodide ions (up to approximately 98%), and a few formed iodide-containing organic compounds, reducing significantly the toxicity of degradation products. Under direct UV irradiation and free radical reduction (mainly e), 15 transformation intermediates of IPM were produced by amide hydrolysis, deiodination, hydroxyl radical addition and hydrogen abstraction reactions, in which free radical attack accounted for the main part. Consequently, the UV/sulfite process has a strong potential for IPM degradation in aquatic environments.
碘帕醇（IPM）广泛应用于医学临床检查和治疗，对生态环境造成了不可估量的危害。本研究开发了紫外光和亚硫酸盐（UV/sulfite）联合工艺来降解 IPM。与单独亚硫酸盐还原几乎没有去除 IPM 相比，UV/sulfite 工艺可以有效地将 IPM 还原降解，观察到的速率常数（k）为 2.08 min，几乎是单独紫外光照射的 4 倍。通过采用活性物质捕获剂，鉴定出 UV/sulfite 工艺中的主要活性物质为水合电子（e）。评价了初始 pH 值、亚硫酸盐用量、IPM 浓度、紫外光强度和常见水基质的影响。在 pH 值为 9 时，仅 2.5 min 内 IPM 的降解就达到近 100%，并且 k 值随着初始亚硫酸盐用量和紫外光强度的增加而增加。HCO 对 IPM 的降解影响有限，而腐殖酸（HA）在 UV/sulfite 工艺中被发现是一种很强的抑制剂。在 UV/sulfite 的协同作用下，IPM 中的大部分碘以碘化物离子的形式释放（高达约 98%），少数形成含碘有机化合物，大大降低了降解产物的毒性。在直接紫外光照射和自由基还原（主要是 e）下，通过酰胺水解、脱碘、羟基自由基加成和氢提取反应，生成了 15 种 IPM 的转化中间产物，其中自由基攻击占主要部分。因此，UV/sulfite 工艺在水环境中具有很强的降解 IPM 的潜力。
